Textbook Question
Sketch the structure of the complex in each of the following compounds and give the full compound name:
d. cis-[Ru(en)2Cl2]
Ch.23 - Transition Metals and Coordination Chemistry
Chapter 23, Problem 74
Complete the exercises below. The square-planar complex [Pt(en) Cl₂] only forms in one of two possible geometric isomers. Which isomer is not observed: cis or trans?
Verified step by step guidance1
Step 1: Understand the structure of the square-planar complex [Pt(en)Cl₂]. The complex consists of a platinum (Pt) center, an ethylenediamine (en) ligand, and two chloride (Cl) ligands.
Step 2: Recognize that square-planar complexes can exhibit geometric isomerism, specifically cis and trans isomers. In the cis isomer, similar ligands are adjacent to each other, while in the trans isomer, similar ligands are opposite each other.
Step 3: Consider the steric and electronic factors that influence the stability of square-planar complexes. Ethylenediamine is a bidentate ligand, meaning it forms two bonds with the metal center, which can affect the spatial arrangement of the ligands.
Step 4: Analyze the potential isomers: In the cis isomer of [Pt(en)Cl₂], the two chloride ligands would be adjacent, while in the trans isomer, they would be opposite each other. Consider how the bidentate nature of ethylenediamine might influence which isomer is more stable.
Step 5: Conclude which isomer is not observed based on the stability considerations. Typically, steric hindrance and electronic effects favor one isomer over the other in square-planar complexes.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Geometric Isomerism
Geometric isomerism occurs in coordination compounds where ligands can be arranged differently around a central metal atom. In square-planar complexes, ligands can be positioned either adjacent to each other (cis) or opposite each other (trans). Understanding this concept is crucial for determining which isomer can exist based on the spatial arrangement of the ligands.
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Guided course
02:02
Geometric Isomers
Square-Planar Geometry
Square-planar geometry is a molecular shape where four ligands are arranged at the corners of a square around a central atom, typically seen in d8 metal complexes like platinum(II). This geometry influences the types of isomers that can form, as the arrangement of ligands affects the overall symmetry and stability of the complex.
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02:07Square planar complexes show the most complex splitting pattern.
Ligand Field Theory
Ligand field theory explains the electronic structure and stability of coordination complexes by considering the interaction between the central metal ion and surrounding ligands. In the case of [Pt(en)Cl₂], the nature of the ligands (bidentate ethylenediamine and monodentate chloride) affects the stability of the isomers, leading to the observation of only one geometric isomer.
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02:40Strong-Field Ligands result in a large Δ and Weak-Field Ligands result in a small Δ.
Related Practice
Textbook Question
The molecule dimethylphosphinoethane [(CH3)2PCH2CH2P(CH3)2, which is abbreviated dmpe] is used as a ligand for some complexes that serve as catalysts. A complex that contains this ligand is Mo(CO)4(dmpe) .
a. Draw the Lewis structure for dmpe, and compare it with ethylenediamine as a coordinating ligand.
b. What is the oxidation state of Mo in Na2[Mo(CN)2(CO)2(dmpe)] ?
c. Sketch the structure of the [Mo(CN)2(CO)2(dmpe)]2- ion, including all the possible isomers.
Textbook Question
Carbon monoxide, CO, is an important ligand in coordination chemistry. When CO is reacted with nickel metal, the product is [Ni(CO)4] which is a toxic, pale yellow liquid.
a. What is the oxidation number for nickel in this compound?
b. Given that [Ni(CO)4] is a diamagnetic molecule with a tetrahedral geometry, what is the electron configuration of nickel in this compound?
c. Write the name for [Ni(CO)4] using the nomenclature rules for coordination compounds.